The effect of one dry needling session on pain, central pain processing, muscle co-contraction and gait characteristics in patients with knee osteoarthritis: a randomized controlled trial

Objectives To assess the immediate and three days postintervention effect of one dry needling session compared to one sham needling session on pain, central pain processing, muscle co-contraction and spatiotemporal parameters during gait in knee osteoarthritis patients. Methods A double-blind randomized controlled trial was conducted. Sixty-one knee osteoarthritis patients were randomly assigned to the dry needling or sham needling group. Primary outcomes were pain and central pain processing. Secondary outcomes included muscle co-contraction and spatiotemporal parameters during gait. Patients were assessed at baseline and 15 min after the intervention, and pain also three days after the intervention. Linear mixed models were used to examine between- and within-group differences. Results No significant between-group differences for pain were found, but within-group scores showed a significant decrease 15 min after sham needling and three days after dry needling. The mean conditioned pain modulation effect measured at the m. Trapezius worsened significantly 15 min after sham needling compared to after dry needling (between-group difference). However, individual conditioned pain modulation percentage scores remained stable over time. Various significant within-group differences were found 15 min after sham needling: a decrease of conditioned pain modulation measured at m. Quadriceps and m. Trapezius and stride- and step-time scores, and an increase in step length and widespread pain pressure threshold. A significant decrease in muscle co-contraction index of the m. Vastus Medialis and Semitendinosus was found as within-group difference 15 min after dry needling. Conclusions Dry needling has no larger effect on pain, central pain processing, muscle co-contraction and gait pattern 15 min and three days postintervention compared to sham needling. Mean conditioned pain modulation scores worsened after sham needling compared to after dry needling. Further research remains necessary.

Vulvodynia—It Is Time to Accept a New Understanding from a Neurobiological Perspective

Vulvodynia is one the most common causes of pain during sexual intercourse in premenopausal women. The burden of vulvodynia in a woman’s life can be devastating due to its consequences in the couple’s sexuality and intimacy, in activities of daily living, and psychological well-being. In recent decades, there has been considerable progress in the understanding of vulvar pain. The most significant change has been the differentiation of vulvar pain secondary to pathology or disease from vulvodynia. However, although it is currently proposed that vulvodynia should be considered as a primary chronic pain condition and, therefore, without an obvious identifiable cause, it is still believed that different inflammatory, genetic, hormonal, muscular factors, etc. may be involved in its development. Advances in pain neuroscience and the central sensitization paradigm have led to a new approach to vulvodynia from a neurobiological perspective. It is proposed that vulvodynia should be understood as complex pain without relevant nociception. Different clinical identifiers of vulvodynia are presented from a neurobiological and psychosocial perspective. In this case, strategies to modulate altered central pain processing is necessary, changing the patient’s erroneous cognitions about their pain, and also reducing fear avoidance-behaviors and the disability of the patient.

POS1096 THE EFFECT OF ONE DRY NEEDLING SESSION ON PAIN AND CENTRAL PAIN PROCESSING IN PATIENTS WITH KNEE OSTEOARTHRITIS: A RANDOMIZED CONTROLLED TRIAL

Background:Osteoarthritis (OA) is the leading cause of chronic disability in the elderly1,2. Abnormal central pain processing (CPP) is present in around 30% of the knee OA patients3 and can be partly induced by peripheral nociception through long term potentiation4. An attempt to resolve abnormal CPP can be to eliminate this nociception5. Myofascial trigger points (MTrPs) are often present in knee OA6, can lead to nociception7 and therefore abnormal CPP if prolonged present8. These are usually defined as hypersensitive tender spots within taut bands of a muscle9. Additionally, both MTrPs and knee OA can induce disturbed motor control, increased co-antagonist activation and modified gait pattern10,11. Dry needling (DN) is often used to deactivate the MTrP and thus resolve the source of nociception, which normally results in reducing pain and restoring muscle dysfunction12. However, studies about the effect of DN on CPP and other outcomes than pain are very limiting. Therefore, more high-quality studies concerning DN and its effects on CPP, muscle features and gait are needed13,14.Objectives:The aim of this randomized controlled trial is to assess the effect of one DN session compared to one sham needling (SN) session on pain (processing), muscle activity and gait in patients with knee OA.Methods:61 patients participated of which 31 were allocated to the DN and 30 to the SN group. Each patient underwent one treatment session. Primary outcomes were pain intensity, measured with questionnaires; and CPP, measured with quantitative sensory testing. Secondary outcomes included muscle co-activation, measured with electromyography; and spatiotemporal parameters, measured with gait analysis. Patients were assessed at baseline, 15 minutes (post 1) and 3 days after intervention (post2- only for the outcome pain). Linear mixed models was used to identify the possible differences over time between the two therapy modalities.Results:The following significant within group differences were observed: decreased pain, stride- and step time and increased widespread pain pressure threshold and step length. A significant between group difference of the conditioned pain modulation score was found, whereas the SN group showed a decrease in difference between the pain pressure threshold scores (with and without conditioning stimulus) and the DN group remained stable. No other significant between or within group differences were detected. However, if we compared both interventions, the change over time for the visual analogue scale (VAS) behaved different in the DN (p<0.05, post 2 - baseline) and SN group (p<0.05, post 1 - baseline and post 2 - post 1).Conclusion:One DN session has no larger effect on all outcome measurements compared to SN. Both therapies seem to be useful to improve pain and widespread pain pressure threshold in short term, however the improvement of pain differs in the groups. Although improvements in some spatiotemporal parameters were observed, it is uncertain they are of clinical relevance or related to treatment. More research is necessary to reveal the ideal number of sessions of DN to improve outcomes and to reveal the effect of DN compared to no treatment, as SN could have hide the real treatment effect.References:[1]Reginster, J. Y. Rheumatol. Oxf. 41 Supp 1, 3–6 (2002)[2]Lespasio, M. J. et al. Perm J 21, 16–183 (2017)[3]Lluch, E. et al. Eur J Pain 18, 1367–75 (2014)[4]Mease, P. J. et al. J. Rheumatol. 38, 1546–1551 (2011)[5]Nijs, J. et al. Expert Opin Pharmacother 15, 1671–83 (2014)[6]Bajaj, P. et al. J. Musculoskelet. Pain 9, 17–33 (2001)[7]Jafri, M. S. Int. Sch. Res. Not. 2014, (2014)[8]Cagnie, B. et al. Curr Pain Headache Rep 17, 348 (2013)[9]Borg-Stein, J. et al. Arch. Phys. Med. Rehabil. 83, S40–S47 (2002)[10]Childs, J. D. et al. Clin. Biomech. 19, 44–9 (2004)[11]Ibarra, J. M. et al. J Pain 12, 1282–8 (2011)[12]Rahou-El-Bachiri, Y. et al. J. Clin. Med. 9, (2020)[13]Stieven, F. F. et al. J. Manipulative Physiol. Ther. (2021)[14]Dor, A. et al. J Bodyw Mov Ther 21, 642–647 (2017)Figure 1.Mean and standard error of VAS scores over time in the DN and SN groupAcknowledgements:I like to thank and acknowledge the contribution of the other executive researchers (Lise Brosens, Ayoub El Bouchaoni, Ben Ceusters, Sven Huybrechts and Mathias Van Loon), the participated dry needling therapists, Dry Needling Ghent, Trigger and the University Hospital of Antwerp.Disclosure of Interests:None declared.

Juvenile primary Fibromyalgia Syndrome: epidemiology, etiology, pathogenesis, clinical manifestations and diagnosis

Juvenile primary fibromyalgia syndrome (JPFS) is a chronic, musculoskeletal pain syndrome affecting children and adolescents, most commonly adolescent girls. The syndrome has a multifactorial etiology, with altered central pain processing playing an important role. The hallmark symptom is severe, widespread musculoskeletal pain. Other symptoms include sleep and mood disturbances, headaches, stiffness, and subjective joint swelling. Physical examination can reveal multiple tender points. The diagnosis is clinical, with defined criteria. Early diagnosis and intervention are important. In this part of the review, we discuss the epidemiology, etiology, pathogenesis, clinical manifestations and diagnosis of JPFS. Part two will focus on treatment and prognosis.

Trans-synaptic spreading of alpha-synuclein pathology through sensory afferents leads to sensory nerve degeneration and neuropathic pain

Pain is a common non-motor symptom of Parkinson’s disease (PD), with current limited knowledge of its pathophysiology. Here, we show that peripheral inoculation of mouse alpha-synuclein (α-Syn) pre-formed fibrils, in a transgenic mouse model of PD, elicited retrograde trans-synaptic spreading of α-Syn pathology (pSer129) across sensory neurons and dorsal nerve roots, reaching central pain processing regions, including the spinal dorsal horn and the projections of the anterolateral system in the central nervous system (CNS). Pathological peripheral to CNS propagation of α-Syn aggregates along interconnected neuronal populations within sensory afferents, was concomitant with impaired nociceptive response, reflected by mechanical allodynia, reduced nerve conduction velocities (sensory and motor) and degeneration of small- and medium-sized myelinated fibers. Our findings show a link between the transneuronal propagation of α-Syn pathology with sensory neuron dysfunction and neuropathic impairment, suggesting promising avenues of investigation into the mechanisms underlying pain in PD.

Altered central pain processing in fibromyalgia—A multimodal neuroimaging case-control study using arterial spin labelling

Fibromyalgia is characterized by chronic pain and a striking discrepancy between objective signs of tissue damage and severity of pain. Function and structural alterations in brain areas involved in pain processing may explain this feature. Previous case-control studies in fibromyalgia focused on acute pain processing using experimentally-evoked pain paradigms. Yet, these studies do not allow conclusions about chronic, stimulus-independent pain. Resting-state cerebral blood flow (rsCBF) acquired by arterial spin labelling (ASL) may be a more accurate marker for chronic pain. The objective was to integrate four different functional and structural neuroimaging markers to evaluate the neural correlate of chronic, stimulus-independent pain using a resting-state paradigm. In line with the pathophysiological concept of enhanced central pain processing we hypothesized that rsCBF is increased in fibromyalgia in areas involved in processing of acute pain. We performed an age matched case-control study of 32 female fibromyalgia patients and 32 pain-free controls and calculated group differences in rsCBF, resting state functional connectivity, grey matter volume and cortical thickness using whole-brain and region of interest analyses. We adjusted all analyses for depression and anxiety. As centrally acting drugs are likely to interfere with neuroimaging markers, we performed a subgroup analysis limited to patients not taking such drugs. We found no differences between cases and controls in rsCBF of the thalamus, the basal ganglia, the insula, the somatosensory cortex, the prefrontal cortex, the anterior cingulum and supplementary motor area as brain areas previously identified to be involved in acute processing in fibromyalgia. The results remained robust across all neuroimaging markers and when limiting the study population to patients not taking centrally acting drugs and matched controls. In conclusion, we found no evidence for functional or structural alterations in brain areas involved in acute pain processing in fibromyalgia that could reflect neural correlates of chronic stimulus-independent pain.

Functional connectivity of the anterior cingulate cortex with pain-related regions in children with post-traumatic headache

Introduction: Post-traumatic headaches (PTH) are common following mild traumatic brain injury (mTBI). There is evidence of altered central pain processing in adult PTH; however, little is known about how children with PTH process pain. The anterior cingulate cortex (ACC) plays a critical role in descending central pain modulation. In this study, we explored whether the functional connectivity (FC) of the ACC is altered in children with PTH. Methods: In this case-control study, we investigated resting-state FC of 5 ACC seeds (caudal, dorsal, rostral, perigenual, and subgenual) in children with PTH ( n = 73) and without PTH ( n = 29) following mTBI, and healthy controls ( n = 27). Post-concussion symptoms were assessed using the Post-Concussion Symptom Inventory and the Child Health Questionnaire. Resting-state functional Magnetic Resonance Imaging (fMRI) data were used to generate maps of ACC FC. Group-level comparisons were performed within a target mask comprised of pain-related regions using FSL Randomise. Results: We found decreased FC between the right perigenual ACC and the left cerebellum, and increased FC between the right subgenual ACC and the left dorsolateral prefrontal cortex in children with PTH compared to healthy controls. The ACC FC in children without PTH following mTBI did not differ from the group with PTH or healthy controls. FC between rostral and perigenual ACC seeds and the cerebellum was increased in children with PTH with pre-injury headaches compared to those with PTH without pre-injury headaches. There was a positive relationship between PTH severity and rostral ACC FC with the bilateral thalamus, right hippocampus and periaqueductal gray. Conclusions: Central pain processing is altered in children with PTH. Pre-existing headaches help to drive this process. Trial registration: The PlayGame Trial was registered in ClinicalTrials.gov database ( ClinicalTrials.gov Identifier: NCT01874847).

DNA methylation changes in genes involved in inflammation and depression in fibromyalgia: a pilot study

ObjectivesThe present pilot study aims to investigate DNA methylation changes of genes related to fibromyalgia (FM) development and its main comorbid symptoms, including sleep impairment, inflammation, depression and other psychiatric disorders. Epigenetic modifications might trigger or perpetuate complex interplay between pain transduction/transmission, central pain processing and experienced stressors in vulnerable individuals.MethodsWe conducted DNA methylation analysis by targeted bisulfite NGS sequencing testing differential methylation in 112 genomic regions from leukocytes of eight women with FM and their eight healthy sisters as controls.ResultsTests for differentially methylated regions and cytosines brought focus on the GRM2 gene, encoding the metabotropic glutamate receptor2. The slightly increased DNA methylation observed in the GRM2 region of FM patients may confirm the involvement of the glutamate pathway in this pathological condition. Logistic regression highlighted the simultaneous association of methylation levels of depression and inflammation-related genes with FM.ConclusionsAltogether, the results evidence the glutamate pathway involvement in FM and support the idea that a combination of methylated and unmethylated genes could represent a risk factor to FM or its consequence, more than single genes. Further studies on the identified biomarkers could contribute to unravel the causative underlying FM mechanisms, giving reliable directions to research, improving the diagnosis and effective therapies.

Transcranial Direct Current Stimulation Combined With Meditation for Older Adults With Knee Osteoarthritis

Osteoarthritis (OA) of the knee is one of the most common causes of pain in older adults. Recent evidence suggests that knee OA pain is characterized by alterations in central pain processing in the brain. Two nonpharmacological pain treatments, transcranial direct current stimulation (tDCS) and mindfulness-based meditation (MBM), have been shown to improve pain-related brain function in older adults with knee OA. Because tDCS promotes neuroplasticity, it may potentiate the effect of MBM that also stimulates adaptive changes in the brain. However, no studies have examined whether tDCS combined with MBM can reduce OA symptoms in older adults with knee OA. Thus, the purpose of this study was to examine the preliminary efficacy of tDCS combined with MBM in older adults with knee OA. Thirty participants with knee OA were randomly assigned to receive 10 daily sessions of home-based 2 mA tDCS combined with active MBM for 20 minutes (n=15) or sham tDCS combined with sham MBM (n=15). We measured OA-related clinical symptoms using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Participants (60% female) had a mean age of 59 years. Active tDCS combined with active MBM significantly reduced scores on the WOAMC (Cohen’s d = 0.83, P = 0.02). Participants tolerated tDCS combined with MBM well without serious adverse effects. Our findings demonstrate promising clinical efficacy of home-based tDCS combined with MBM for older adults with knee OA. Future studies with larger-scale randomized controlled trials with follow-up assessments are needed to validate our findings.